The invention is relative to a catch (clasp) on a pressring (shaping ring) with several cheek plate elements connected to each other in an articulated fashion, with a coupling element with which the cheek plate elements adjacent to a closed position and comprising a coupling bolt for a closing device can be provisionally connected.
A clasp of this type is known in the state of the art from EP 0671984. It comprises a coupling element which has a first coupling shackle articulated to a cheek plate element and a second coupling shackle connected to the other cheek plate element. These two coupling shackles can be connected by a coupling bolt which engages into both and which must be rotated to close the coupling member. In the coupled state, the coupling member is designed to be flexible.
The present invention creates a clasp of the cited type which can be produced in a simpler and more economical manner and, in addition, is simpler to manipulate.
The present invention solves the problems of a generic clasp in that the coupling element of the present invention is a bracket [curved piece of metal] mounted so that it can pivot on its one end on the coupling bolt of the one cheek plate element and which can be connected by its other end to the other cheek plate element in such a manner that this other end is movably mounted on the other cheek plate element in the coupled position.
In the clasp according to the invention the coupling element is a bracket movably mounted on its pivotable end in the locking position on the shaping ring. During the closing of the shaping ring a shifting occurs between the bracket and the one cheek plate element of the shaping ring. This has the significant advantage that the coupling element does not have to be designed to be flexible. This can avoid expensive articulations. The bracket can be produced in a very simple manner from a rigid wire. In a preferred embodiment the bracket is a wire bracket which is essentially U-shaped when viewed in the radial direction of the cheek plate. The bracket can therefore be manufactured in a very simple manner from a piece of wire. Even the manipulating of the clasp in accordance with the invention is very simple. In order to provisionally close the shaping ring all that is necessary is to pivot the bracket into the locking position. To open it the bracket is pivoted in the opposite direction.
The manufacture is particularly simple if the bracket is mounted on the coupling bolts provided for the closing device. One of these coupling bolts serves with its projecting ends consisting of joint bolts for the bracket and other coupling bolt serves in cooperation with the bend of the bracket to determine the opening width of the shaping ring in the coupled position.
According to a further development of the invention at least one cheek plate element adjacent to the closed position comprises at least one projection with which the bracket is locked in its closed position. During the closing of the shaping ring the bracket slides along this projection. The bracket thus remains fixed during the closing of the shaping ring and can be loosened after the pressing procedure by being pivoted. Such a projection can be realized, for example, in a very economical manner as a comparatively short, formed-on cam.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.